The travel alert for Hong Kong travellers remains at amber — the lowest of the three-level alert system.

He said about 500 Hong Kong tourists were touring Thailand.

UK Minister of State for the Foreign and Commonwealth office, Hugo Swire, said he took heart from the army's assurance that the invocation of martial law is not a coup.

"We expect them to remain true to their word. I call on the military to act in accordance with international human rights standards and the rule of law, and respect democratic principles and institutions,'' he said.

New Zealand's Foreign Affairs and Trade Ministry spokesman advised the 990 New Zealand nationals currently in Thailand to avoid all rallies, demonstrations and large public gatherings.